<!DOCTYPE HTML>
<html lang="zh-CN">


<head>
    <meta charset="utf-8">
    <meta name="keywords" content="Java学习笔记, study">
    <meta name="description" content="">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <meta name="renderer" content="webkit|ie-stand|ie-comp">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="format-detection" content="telephone=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
    <!-- Global site tag (gtag.js) - Google Analytics -->


    <title>Java学习笔记 | 今夕清欢</title>

    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/artitalk/artitalk.min.css">
    <link rel="icon" type="image/png" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/favicon.png">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/awesome/css/all.css">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/materialize/materialize.min.css">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/aos/aos.css">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/animate/animate.min.css">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/lightGallery/css/lightgallery.min.css">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/css/matery.css">
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/css/my.css">

    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/jquery/jquery.min.js"></script>

<meta name="generator" content="Hexo 4.2.0"><link rel="alternate" href="/atom.xml" title="今夕清欢" type="application/atom+xml">
<link rel="stylesheet" href="/css/prism-hopscotch.css" type="text/css"></head>



   <style>
    body{
       background-image: url(https://cdn.jsdelivr.net/gh/Tokisaki-Galaxy/res/site/medias/background.jpg);
       background-repeat:no-repeat;
       background-size:cover;
       background-attachment:fixed;
    }
</style>



<body>
    <header class="navbar-fixed">
    <nav id="headNav" class="bg-color nav-transparent">
        <div id="navContainer" class="nav-wrapper container">
            <div class="brand-logo">
                <a href="/" class="waves-effect waves-light">
                    
                    <img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/logo.png" class="logo-img" alt="LOGO">
                    
                    <span class="logo-span">今夕清欢</span>
                </a>
            </div>
            

<a href="#" data-target="mobile-nav" class="sidenav-trigger button-collapse"><i class="fas fa-bars"></i></a>
<ul class="right nav-menu">
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/" class="waves-effect waves-light">
      
      <i class="fas fa-home" style="zoom: 0.6;"></i>
      
      <span>首页</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/tags" class="waves-effect waves-light">
      
      <i class="fas fa-tags" style="zoom: 0.6;"></i>
      
      <span>标签</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/categories" class="waves-effect waves-light">
      
      <i class="fas fa-bookmark" style="zoom: 0.6;"></i>
      
      <span>分类</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/archives" class="waves-effect waves-light">
      
      <i class="fas fa-archive" style="zoom: 0.6;"></i>
      
      <span>归档</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/artitalk" class="waves-effect waves-light">
      
      <i class="fas fa-heartbeat" style="zoom: 0.6;"></i>
      
      <span>说说</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/about" class="waves-effect waves-light">
      
      <i class="fas fa-user-circle" style="zoom: 0.6;"></i>
      
      <span>关于</span>
    </a>
    
  </li>
  
  <li>
    <a href="#searchModal" class="modal-trigger waves-effect waves-light">
      <i id="searchIcon" class="fas fa-search" title="搜索" style="zoom: 0.85;"></i>
    </a>
  </li>
</ul>


<div id="mobile-nav" class="side-nav sidenav">

    <div class="mobile-head bg-color">
        
        <img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/logo.png" class="logo-img circle responsive-img">
        
        <div class="logo-name">今夕清欢</div>
        <div class="logo-desc">
            
            Never really desperate, only the lost of the soul.
            
        </div>
    </div>

    

    <ul class="menu-list mobile-menu-list">
        
        <li class="m-nav-item">
	  
		<a href="/" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-home"></i>
			
			首页
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/tags" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-tags"></i>
			
			标签
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/categories" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-bookmark"></i>
			
			分类
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/archives" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-archive"></i>
			
			归档
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/artitalk" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-heartbeat"></i>
			
			ArtiTalk
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/about" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-user-circle"></i>
			
			关于
		</a>
          
        </li>
        
        
        <li><div class="divider"></div></li>
        <li>
            <a href="https://github.com/jinxiqinghuan" class="waves-effect waves-light" target="_blank">
                <i class="fab fa-github-square fa-fw"></i>Fork Me
            </a>
        </li>
        
    </ul>
</div>


        </div>

        
            <style>
    .nav-transparent .github-corner {
        display: none !important;
    }

    .github-corner {
        position: absolute;
        z-index: 10;
        top: 0;
        right: 0;
        border: 0;
        transform: scale(1.1);
    }

    .github-corner svg {
        color: #0f9d58;
        fill: #fff;
        height: 64px;
        width: 64px;
    }

    .github-corner:hover .octo-arm {
        animation: a 0.56s ease-in-out;
    }

    .github-corner .octo-arm {
        animation: none;
    }

    @keyframes a {
        0%,
        to {
            transform: rotate(0);
        }
        20%,
        60% {
            transform: rotate(-25deg);
        }
        40%,
        80% {
            transform: rotate(10deg);
        }
    }
</style>

<a href="https://github.com/jinxiqinghuan" class="github-corner tooltipped hide-on-med-and-down" target="_blank"
   data-tooltip="Fork Me" data-position="left" data-delay="50">
    <svg viewBox="0 0 250 250" aria-hidden="true">
        <path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"></path>
        <path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2"
              fill="currentColor" style="transform-origin: 130px 106px;" class="octo-arm"></path>
        <path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z"
              fill="currentColor" class="octo-body"></path>
    </svg>
</a>
        
    </nav>

</header>

    
<script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/cryptojs/crypto-js.min.js"></script>
<script>
    (function() {
        let pwd = '';
        if (pwd && pwd.length > 0) {
            if (pwd !== CryptoJS.SHA256(prompt('请输入访问本文章的密码')).toString(CryptoJS.enc.Hex)) {
                alert('密码错误，将返回主页！');
                location.href = '/';
            }
        }
    })();
</script>




<div class="bg-cover pd-header post-cover" style="background-image: url('https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/featureimages/8.jpg')">
    <div class="container" style="right: 0px;left: 0px;">
        <div class="row">
            <div class="col s12 m12 l12">
                <div class="brand">
                    <h1 class="description center-align post-title">Java学习笔记</h1>
                </div>
            </div>
        </div>
    </div>
</div>




<main class="post-container content">

    
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/tocbot/tocbot.css">
<style>
    #articleContent h1::before,
    #articleContent h2::before,
    #articleContent h3::before,
    #articleContent h4::before,
    #articleContent h5::before,
    #articleContent h6::before {
        display: block;
        content: " ";
        height: 100px;
        margin-top: -100px;
        visibility: hidden;
    }

    #articleContent :focus {
        outline: none;
    }

    .toc-fixed {
        position: fixed;
        top: 64px;
    }

    .toc-widget {
        width: 345px;
        padding-left: 20px;
    }

    .toc-widget .toc-title {
        margin: 35px 0 15px 0;
        padding-left: 17px;
        font-size: 1.5rem;
        font-weight: bold;
        line-height: 1.5rem;
    }

    .toc-widget ol {
        padding: 0;
        list-style: none;
    }

    #toc-content {
        height: calc(100vh - 250px);
        overflow: auto;
    }

    #toc-content ol {
        padding-left: 10px;
    }

    #toc-content ol li {
        padding-left: 10px;
    }

    #toc-content .toc-link:hover {
        color: #42b983;
        font-weight: 700;
        text-decoration: underline;
    }

    #toc-content .toc-link::before {
        background-color: transparent;
        max-height: 25px;

        position: absolute;
        right: 23.5vw;
        display: block;
    }

    #toc-content .is-active-link {
        color: #42b983;
    }

    #floating-toc-btn {
        position: fixed;
        right: 15px;
        bottom: 76px;
        padding-top: 15px;
        margin-bottom: 0;
        z-index: 998;
    }

    #floating-toc-btn .btn-floating {
        width: 48px;
        height: 48px;
    }

    #floating-toc-btn .btn-floating i {
        line-height: 48px;
        font-size: 1.4rem;
    }
</style>
<div class="row">
    <div id="main-content" class="col s12 m12 l9">
        <!-- 文章内容详情 -->
<div id="artDetail">
    <div class="card">
        <div class="card-content article-info">
            <div class="row tag-cate">
                <div class="col s7">
                    
                    <div class="article-tag">
                        
                            <a href="/tags/Java/">
                                <span class="chip bg-color">Java</span>
                            </a>
                        
                            <a href="/tags/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%E7%B3%BB%E5%88%97/">
                                <span class="chip bg-color">学习笔记系列</span>
                            </a>
                        
                    </div>
                    
                </div>
                <div class="col s5 right-align">
                    
                    <div class="post-cate">
                        <i class="fas fa-bookmark fa-fw icon-category"></i>
                        
                            <a href="/categories/Java/" class="post-category">
                                Java
                            </a>
                        
                    </div>
                    
                </div>
            </div>

            <div class="post-info">
                
                <div class="post-date info-break-policy">
                    <i class="far fa-calendar-minus fa-fw"></i>发布日期:&nbsp;&nbsp;
                    2020-10-13
                </div>
                

                
                <div class="post-date info-break-policy">
                    <i class="far fa-calendar-check fa-fw"></i>更新日期:&nbsp;&nbsp;
                    2020-10-18
                </div>
                

                
                <div class="info-break-policy">
                    <i class="far fa-file-word fa-fw"></i>文章字数:&nbsp;&nbsp;
                    1.1k
                </div>
                

                
                <div class="info-break-policy">
                    <i class="far fa-clock fa-fw"></i>阅读时长:&nbsp;&nbsp;
                    5 分
                </div>
                

                
                    <div id="busuanzi_container_page_pv" class="info-break-policy">
                        <i class="far fa-eye fa-fw"></i>阅读次数:&nbsp;&nbsp;
                        <span id="busuanzi_value_page_pv"></span>
                    </div>
				
            </div>
        </div>
        <hr class="clearfix">
        <div class="card-content article-card-content">
            <div id="articleContent">
                <h1 id="Java学习笔记"><a href="#Java学习笔记" class="headerlink" title="Java学习笔记"></a>Java学习笔记</h1><h2 id="Java基础"><a href="#Java基础" class="headerlink" title="Java基础"></a>Java基础</h2><h3 id="B站博学谷基础课程"><a href="#B站博学谷基础课程" class="headerlink" title="B站博学谷基础课程"></a>B站博学谷基础课程</h3><p>地址： <a href="https://www.bilibili.com/video/BV1Wx411f7qN" target="_blank" rel="noopener">https://www.bilibili.com/video/BV1Wx411f7qN</a></p>
<p>特点：简单讲授了Java的基础语法，但太基础，不适合有一定变成基础的人，适合跳跃着看。</p>
<h5 id="增强for和迭代器"><a href="#增强for和迭代器" class="headerlink" title="增强for和迭代器"></a>增强for和迭代器</h5><ul>
<li>增强for</li>
</ul>
<pre class=" language-java"><code class="language-java"><span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo8<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>ArrayList<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>List<span class="token punctuation">;</span>

<span class="token comment" spellcheck="true">//增强for格式遍历数组或集合对象</span>
<span class="token comment" spellcheck="true">//快捷方式iter</span>
<span class="token comment" spellcheck="true">//增强for的底层依赖的是迭代器（Iterator）</span>
<span class="token comment" spellcheck="true">//增强for就是迭代器的简写形式</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        List list <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">30</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">40</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">for</span><span class="token punctuation">(</span>Object obj<span class="token operator">:</span>list<span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token comment" spellcheck="true">//obj是集合中的元素，其本身应该是Integer类型的数据</span>
            Integer ii <span class="token operator">=</span> <span class="token punctuation">(</span>Integer<span class="token punctuation">)</span>obj<span class="token punctuation">;</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>obj<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<ul>
<li>迭代器遍历List集合</li>
</ul>
<pre class=" language-java"><code class="language-java"><span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo8<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>ArrayList<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Iterator<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>List<span class="token punctuation">;</span>

<span class="token comment" spellcheck="true">//通过迭代器遍历List集合</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test2</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        List list <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"a"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"b"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"c"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        Iterator it <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">iterator</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">while</span> <span class="token punctuation">(</span>it<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            String s <span class="token operator">=</span> <span class="token punctuation">(</span>String<span class="token punctuation">)</span>it<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"--------------"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token keyword">while</span> <span class="token punctuation">(</span>it<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            String s <span class="token operator">=</span> <span class="token punctuation">(</span>String<span class="token punctuation">)</span>it<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token comment" spellcheck="true">//不使用s.equals("b")，使用以下方式能够规避空指针异常的情况</span>
            <span class="token keyword">if</span><span class="token punctuation">(</span><span class="token string">"b"</span><span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
                <span class="token comment" spellcheck="true">//能走到这里，说明集合中有元素b</span>
                list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"java"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  <span class="token comment" spellcheck="true">//报错，并发修改异常</span>
            <span class="token punctuation">}</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<ul>
<li>并发异常优化<br>关于上述案例中出现的并发异常的优化方法</li>
</ul>
<pre class=" language-java"><code class="language-java"><span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo8<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>ArrayList<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>List<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>ListIterator<span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test3</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        List list <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"a"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"b"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"c"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        ListIterator lit <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">listIterator</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">while</span> <span class="token punctuation">(</span>lit<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            String s <span class="token operator">=</span><span class="token punctuation">(</span>String<span class="token punctuation">)</span>lit<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token string">"b"</span><span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
                <span class="token comment" spellcheck="true">//list.add("java")  //这样写不行，必须调用列表迭代器的方法实现</span>
                lit<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"java"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token punctuation">}</span>
        <span class="token punctuation">}</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>list<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<h4 id="泛型"><a href="#泛型" class="headerlink" title="泛型"></a>泛型</h4><pre class=" language-java"><code class="language-java"><span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo9<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>ArrayList<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>List<span class="token punctuation">;</span>

<span class="token comment" spellcheck="true">//泛型</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token comment" spellcheck="true">//不使用泛型的集合</span>
        List list1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list1<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"a"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list1<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"b"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list1<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"c"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token comment" spellcheck="true">//list1.add(10);  //会报类型转换异常</span>

        <span class="token keyword">for</span> <span class="token punctuation">(</span>Object obj <span class="token operator">:</span> list1<span class="token punctuation">)</span> <span class="token punctuation">{</span>
            String s <span class="token operator">=</span> <span class="token punctuation">(</span>String<span class="token punctuation">)</span>obj<span class="token punctuation">;</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"--------------"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token comment" spellcheck="true">//使用泛型类型更安全，避免了类型转换</span>
        <span class="token comment" spellcheck="true">//泛型一般只和集合类配合使用</span>
        List<span class="token operator">&lt;</span>String<span class="token operator">></span> list2 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token operator">&lt;</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list2<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"abc"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list2<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"def"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list2<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token string">"hjk"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token keyword">for</span> <span class="token punctuation">(</span>String s <span class="token operator">:</span> list2<span class="token punctuation">)</span> <span class="token punctuation">{</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<h4 id="Collections工具类"><a href="#Collections工具类" class="headerlink" title="Collections工具类"></a>Collections工具类</h4><pre class=" language-java"><code class="language-java"><span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo10<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>ArrayList<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Collections<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>List<span class="token punctuation">;</span>

<span class="token comment" spellcheck="true">//Collections</span>
<span class="token comment" spellcheck="true">//针对集合进行操作的工具类</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        List<span class="token operator">&lt;</span>Integer<span class="token operator">></span> list <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token operator">&lt;</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"没有操作以前，集合中的元素是： "</span> <span class="token operator">+</span> list<span class="token punctuation">)</span><span class="token punctuation">;</span>

        Integer max <span class="token operator">=</span> Collections<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>list<span class="token punctuation">)</span><span class="token punctuation">;</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"集合中的最大元素是："</span> <span class="token operator">+</span> max<span class="token punctuation">)</span><span class="token punctuation">;</span>

        Collections<span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>list<span class="token punctuation">)</span><span class="token punctuation">;</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"升序后的排列结果为： "</span> <span class="token operator">+</span> list<span class="token punctuation">)</span><span class="token punctuation">;</span>

        Collections<span class="token punctuation">.</span><span class="token function">reverse</span><span class="token punctuation">(</span>list<span class="token punctuation">)</span><span class="token punctuation">;</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"翻转以后集合中的数据为： "</span> <span class="token operator">+</span> list<span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token comment" spellcheck="true">//可以利用升序和翻转，来实现降序</span>

        Collections<span class="token punctuation">.</span><span class="token function">shuffle</span><span class="token punctuation">(</span>list<span class="token punctuation">)</span><span class="token punctuation">;</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"随机置换的结果为： "</span> <span class="token operator">+</span> list<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<h4 id="Set集合"><a href="#Set集合" class="headerlink" title="Set集合"></a>Set集合</h4><p>以下成员程序在运行时，一直输出地址值而不输出内容，待排查</p>
<pre class=" language-java"><code class="language-java">
Student<span class="token punctuation">.</span>java<span class="token operator">:</span>
<span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo11<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Objects<span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Student</span> <span class="token punctuation">{</span>
    <span class="token keyword">private</span> String name<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> age<span class="token punctuation">;</span>

    <span class="token keyword">public</span> <span class="token function">Student</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token function">Student</span><span class="token punctuation">(</span>String name<span class="token punctuation">,</span> <span class="token keyword">int</span> age<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>age <span class="token operator">=</span> age<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> String <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getAge</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> age<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setAge</span><span class="token punctuation">(</span><span class="token keyword">int</span> age<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>age <span class="token operator">=</span> age<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token annotation punctuation">@Override</span>
    <span class="token keyword">public</span> <span class="token keyword">boolean</span> <span class="token function">equals</span><span class="token punctuation">(</span>Object o<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">this</span> <span class="token operator">==</span> o<span class="token punctuation">)</span> <span class="token keyword">return</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
        <span class="token keyword">if</span> <span class="token punctuation">(</span>o <span class="token operator">==</span> null <span class="token operator">||</span> <span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">!=</span> o<span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token keyword">return</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
        Student student <span class="token operator">=</span> <span class="token punctuation">(</span>Student<span class="token punctuation">)</span> o<span class="token punctuation">;</span>
        <span class="token keyword">return</span> age <span class="token operator">==</span> student<span class="token punctuation">.</span>age <span class="token operator">&amp;&amp;</span>
                Objects<span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>name<span class="token punctuation">,</span> student<span class="token punctuation">.</span>name<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token annotation punctuation">@Override</span>
    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">hashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> Objects<span class="token punctuation">.</span><span class="token function">hash</span><span class="token punctuation">(</span>name<span class="token punctuation">,</span> age<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>


Test<span class="token punctuation">.</span>java<span class="token operator">:</span>
<span class="token keyword">package</span> cn<span class="token punctuation">.</span>tools<span class="token punctuation">.</span>demo11<span class="token punctuation">;</span>

<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>HashSet<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Iterator<span class="token punctuation">;</span>
<span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Set<span class="token punctuation">;</span>

<span class="token comment" spellcheck="true">//单集合Collection之Set集合</span>
<span class="token comment" spellcheck="true">//无序、唯一</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        Set<span class="token operator">&lt;</span>Student<span class="token operator">></span> ss <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashSet</span><span class="token operator">&lt;</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        Student s1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"乔峰"</span><span class="token punctuation">,</span> <span class="token number">41</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        Student s2 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"段誉"</span><span class="token punctuation">,</span><span class="token number">38</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        Student s3 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"虚竹"</span><span class="token punctuation">,</span> <span class="token number">26</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        Student s4 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"段誉"</span><span class="token punctuation">,</span><span class="token number">38</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        Student s5 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"虚竹"</span><span class="token punctuation">,</span> <span class="token number">26</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        ss<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ss<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s2<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ss<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s3<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ss<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s4<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ss<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s5<span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token comment" spellcheck="true">/*
        为什么Set集合没有去重？
            因为Set集合保证元素的唯一性依赖：equal()和hashCode()两个方法
            你没有在Student类中重写这两个方法，默认调用的是Object类中的这两个方法
            而Object类中的equal()方法默认比较的是地址值是否相同
            解决方案:重写
         */</span>

        <span class="token comment" spellcheck="true">//迭代器遍历Set集合</span>
        System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">print</span><span class="token punctuation">(</span>ss<span class="token punctuation">)</span><span class="token punctuation">;</span>
        Iterator<span class="token operator">&lt;</span>Student<span class="token operator">></span> it <span class="token operator">=</span> ss<span class="token punctuation">.</span><span class="token function">iterator</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">while</span> <span class="token punctuation">(</span>it<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>it<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

        <span class="token comment" spellcheck="true">//通过增强for遍历Set集合</span>
        <span class="token keyword">for</span> <span class="token punctuation">(</span>Student student <span class="token operator">:</span> ss<span class="token punctuation">)</span> <span class="token punctuation">{</span>
            System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>student<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

    <span class="token punctuation">}</span>
<span class="token punctuation">}</span></code></pre>
<h4 id="Map集合"><a href="#Map集合" class="headerlink" title="Map集合"></a>Map集合</h4><pre class=" language-java"><code class="language-java">
</code></pre>
<h3 id="尚硅谷宋红康老师Java课程"><a href="#尚硅谷宋红康老师Java课程" class="headerlink" title="尚硅谷宋红康老师Java课程"></a>尚硅谷宋红康老师Java课程</h3><p>链接： <a href="https://www.bilibili.com/video/BV1Kb411W75N?t=121&amp;p=370" target="_blank" rel="noopener">https://www.bilibili.com/video/BV1Kb411W75N?t=121&amp;p=370</a></p>
<p>特点： 详细具体</p>
<h4 id="异常处理"><a href="#异常处理" class="headerlink" title="异常处理"></a>异常处理</h4><h2 id="Spring学习"><a href="#Spring学习" class="headerlink" title="Spring学习"></a>Spring学习</h2><h3 id="Spring-boot"><a href="#Spring-boot" class="headerlink" title="Spring boot"></a>Spring boot</h3>
            </div>
            <hr/>

            

    <div class="reprint" id="reprint-statement">
        
            <div class="reprint__author">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-user">
                        文章作者:
                    </i>
                </span>
                <span class="reprint-info">
                    <a href="/about" rel="external nofollow noreferrer">qinghuan</a>
                </span>
            </div>
            <div class="reprint__type">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-link">
                        文章链接:
                    </i>
                </span>
                <span class="reprint-info">
                    <a href="https://jinxiqinghuan.github.io/2020/10/13/java-xue-xi-bi-ji/">https://jinxiqinghuan.github.io/2020/10/13/java-xue-xi-bi-ji/</a>
                </span>
            </div>
            <div class="reprint__notice">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-copyright">
                        版权声明:
                    </i>
                </span>
                <span class="reprint-info">
                    本博客所有文章除特別声明外，均采用
                    <a href="https://creativecommons.org/licenses/by/4.0/deed.zh" rel="external nofollow noreferrer" target="_blank">CC BY 4.0</a>
                    许可协议。转载请注明来源
                    <a href="/about" target="_blank">qinghuan</a>
                    !
                </span>
            </div>
        
    </div>

    <script async defer>
      document.addEventListener("copy", function (e) {
        let toastHTML = '<span>复制成功，请遵循本文的转载规则</span><button class="btn-flat toast-action" onclick="navToReprintStatement()" style="font-size: smaller">查看</a>';
        M.toast({html: toastHTML})
      });

      function navToReprintStatement() {
        $("html, body").animate({scrollTop: $("#reprint-statement").offset().top - 80}, 800);
      }
    </script>



            <div class="tag_share" style="display: block;">
                <div class="post-meta__tag-list" style="display: inline-block;">
                    
                        <div class="article-tag">
                            
                                <a href="/tags/Java/">
                                    <span class="chip bg-color">Java</span>
                                </a>
                            
                                <a href="/tags/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%E7%B3%BB%E5%88%97/">
                                    <span class="chip bg-color">学习笔记系列</span>
                                </a>
                            
                        </div>
                    
                </div>
                <div class="post_share" style="zoom: 80%; width: fit-content; display: inline-block; float: right; margin: -0.15rem 0;">
                    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/share/css/share.min.css">
<div id="article-share">

    
    <div class="social-share" data-sites="twitter,facebook,google,qq,qzone,wechat,weibo,douban,linkedin" data-wechat-qrcode-helper="<p>微信扫一扫即可分享！</p>"></div>
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/share/js/social-share.min.js"></script>
    

    

</div>

                </div>
            </div>
            
                <style>
    #reward {
        margin: 40px 0;
        text-align: center;
    }

    #reward .reward-link {
        font-size: 1.4rem;
        line-height: 38px;
    }

    #reward .btn-floating:hover {
        box-shadow: 0 6px 12px rgba(0, 0, 0, 0.2), 0 5px 15px rgba(0, 0, 0, 0.2);
    }

    #rewardModal {
        width: 320px;
        height: 350px;
    }

    #rewardModal .reward-title {
        margin: 15px auto;
        padding-bottom: 5px;
    }

    #rewardModal .modal-content {
        padding: 10px;
    }

    #rewardModal .close {
        position: absolute;
        right: 15px;
        top: 15px;
        color: rgba(0, 0, 0, 0.5);
        font-size: 1.3rem;
        line-height: 20px;
        cursor: pointer;
    }

    #rewardModal .close:hover {
        color: #ef5350;
        transform: scale(1.3);
        -moz-transform:scale(1.3);
        -webkit-transform:scale(1.3);
        -o-transform:scale(1.3);
    }

    #rewardModal .reward-tabs {
        margin: 0 auto;
        width: 210px;
    }

    .reward-tabs .tabs {
        height: 38px;
        margin: 10px auto;
        padding-left: 0;
    }

    .reward-content ul {
        padding-left: 0 !important;
    }

    .reward-tabs .tabs .tab {
        height: 38px;
        line-height: 38px;
    }

    .reward-tabs .tab a {
        color: #fff;
        background-color: #ccc;
    }

    .reward-tabs .tab a:hover {
        background-color: #ccc;
        color: #fff;
    }

    .reward-tabs .wechat-tab .active {
        color: #fff !important;
        background-color: #22AB38 !important;
    }

    .reward-tabs .alipay-tab .active {
        color: #fff !important;
        background-color: #019FE8 !important;
    }

    .reward-tabs .reward-img {
        width: 210px;
        height: 210px;
    }
</style>

<div id="reward">
    <a href="#rewardModal" class="reward-link modal-trigger btn-floating btn-medium waves-effect waves-light red">赏</a>

    <!-- Modal Structure -->
    <div id="rewardModal" class="modal">
        <div class="modal-content">
            <a class="close modal-close"><i class="fas fa-times"></i></a>
            <h4 class="reward-title">你的赏识是我前进的动力</h4>
            <div class="reward-content">
                <div class="reward-tabs">
                    <ul class="tabs row">
                        <li class="tab col s6 alipay-tab waves-effect waves-light"><a href="#alipay">支付宝</a></li>
                        <li class="tab col s6 wechat-tab waves-effect waves-light"><a href="#wechat">微 信</a></li>
                    </ul>
                    <div id="alipay">
                        <img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/reward/alipay.jpg" class="reward-img" alt="支付宝打赏二维码">
                    </div>
                    <div id="wechat">
                        <img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/reward/wechat.png" class="reward-img" alt="微信打赏二维码">
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>

<script>
    $(function () {
        $('.tabs').tabs();
    });
</script>

            
        </div>
    </div>

    

    

    

    

    

    

    

<article id="prenext-posts" class="prev-next articles">
    <div class="row article-row">
        
        <div class="article col s12 m6" data-aos="fade-up">
            <div class="article-badge left-badge text-color">
                <i class="fas fa-chevron-left"></i>&nbsp;上一篇</div>
            <div class="card">
                <a href="/2020/12/23/c-primer-plus-ke-hou-bian-cheng-xi-ti/">
                    <div class="card-image">
                        
                        
                        <img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/featureimages/15.jpg" class="responsive-img" alt="C Primer Plus课后编程习题">
                        
                        <span class="card-title">C Primer Plus课后编程习题</span>
                    </div>
                </a>
                <div class="card-content article-content">
                    <div class="summary block-with-text">
                        
                            所有程序都运行过，部分题目存在的问题已经标注，欢迎指正。
                        
                    </div>
                    <div class="publish-info">
                        <span class="publish-date">
                            <i class="far fa-clock fa-fw icon-date"></i>2020-12-23
                        </span>
                        <span class="publish-author">
                            
                            <i class="fas fa-bookmark fa-fw icon-category"></i>
                            
                            <a href="/categories/C/" class="post-category">
                                    C
                                </a>
                            
                            
                        </span>
                    </div>
                </div>
                
                <div class="card-action article-tags">
                    
                    <a href="/tags/C/">
                        <span class="chip bg-color">C</span>
                    </a>
                    
                </div>
                
            </div>
        </div>
        
        
        <div class="article col s12 m6" data-aos="fade-up">
            <div class="article-badge right-badge text-color">
                下一篇&nbsp;<i class="fas fa-chevron-right"></i>
            </div>
            <div class="card">
                <a href="/2020/09/28/linux-jiao-ben-shi-li-jian-dan-jiao-ben-shi-xian-zi-dong-geng-xin-wang-zhan/">
                    <div class="card-image">
                        
                        
                        <img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/featureimages/18.jpg" class="responsive-img" alt="Linux脚本示例——简单脚本实现自动更新博客">
                        
                        <span class="card-title">Linux脚本示例——简单脚本实现自动更新博客</span>
                    </div>
                </a>
                <div class="card-content article-content">
                    <div class="summary block-with-text">
                        
                            
                        
                    </div>
                    <div class="publish-info">
                            <span class="publish-date">
                                <i class="far fa-clock fa-fw icon-date"></i>2020-09-28
                            </span>
                        <span class="publish-author">
                            
                            <i class="fas fa-bookmark fa-fw icon-category"></i>
                            
                            <a href="/categories/%E5%89%8D%E7%AB%AF/" class="post-category">
                                    前端
                                </a>
                            
                            <a href="/categories/%E5%89%8D%E7%AB%AF/Shell/" class="post-category">
                                    Shell
                                </a>
                            
                            
                        </span>
                    </div>
                </div>
                
                <div class="card-action article-tags">
                    
                    <a href="/tags/shell%E8%84%9A%E6%9C%AC/">
                        <span class="chip bg-color">shell脚本</span>
                    </a>
                    
                </div>
                
            </div>
        </div>
        
    </div>
</article>

</div>



<!-- 代码块功能依赖 -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/codeBlock/codeBlockFuction.js"></script>

<!-- 代码语言 -->

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/codeBlock/codeLang.js"></script>


<!-- 代码块复制 -->

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/codeBlock/codeCopy.js"></script>


<!-- 代码块收缩 -->

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/codeBlock/codeShrink.js"></script>


<!-- 代码块折行 -->

<style type="text/css">
code[class*="language-"], pre[class*="language-"] { white-space: pre !important; }
</style>


    </div>
    <div id="toc-aside" class="expanded col l3 hide-on-med-and-down">
        <div class="toc-widget" style="background-color: white;">
            <div class="toc-title"><i class="far fa-list-alt"></i>&nbsp;&nbsp;目录</div>
            <div id="toc-content"></div>
        </div>
    </div>
</div>

<!-- TOC 悬浮按钮. -->

<div id="floating-toc-btn" class="hide-on-med-and-down">
    <a class="btn-floating btn-large bg-color">
        <i class="fas fa-list-ul"></i>
    </a>
</div>


<script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/tocbot/tocbot.min.js"></script>
<script>
    $(function () {
        tocbot.init({
            tocSelector: '#toc-content',
            contentSelector: '#articleContent',
            headingsOffset: -($(window).height() * 0.4 - 45),
            collapseDepth: Number('0'),
            headingSelector: 'h2, h3, h4'
        });

        // modify the toc link href to support Chinese.
        let i = 0;
        let tocHeading = 'toc-heading-';
        $('#toc-content a').each(function () {
            $(this).attr('href', '#' + tocHeading + (++i));
        });

        // modify the heading title id to support Chinese.
        i = 0;
        $('#articleContent').children('h2, h3, h4').each(function () {
            $(this).attr('id', tocHeading + (++i));
        });

        // Set scroll toc fixed.
        let tocHeight = parseInt($(window).height() * 0.4 - 64);
        let $tocWidget = $('.toc-widget');
        $(window).scroll(function () {
            let scroll = $(window).scrollTop();
            /* add post toc fixed. */
            if (scroll > tocHeight) {
                $tocWidget.addClass('toc-fixed');
            } else {
                $tocWidget.removeClass('toc-fixed');
            }
        });

        
        /* 修复文章卡片 div 的宽度. */
        let fixPostCardWidth = function (srcId, targetId) {
            let srcDiv = $('#' + srcId);
            if (srcDiv.length === 0) {
                return;
            }

            let w = srcDiv.width();
            if (w >= 450) {
                w = w + 21;
            } else if (w >= 350 && w < 450) {
                w = w + 18;
            } else if (w >= 300 && w < 350) {
                w = w + 16;
            } else {
                w = w + 14;
            }
            $('#' + targetId).width(w);
        };

        // 切换TOC目录展开收缩的相关操作.
        const expandedClass = 'expanded';
        let $tocAside = $('#toc-aside');
        let $mainContent = $('#main-content');
        $('#floating-toc-btn .btn-floating').click(function () {
            if ($tocAside.hasClass(expandedClass)) {
                $tocAside.removeClass(expandedClass).hide();
                $mainContent.removeClass('l9');
            } else {
                $tocAside.addClass(expandedClass).show();
                $mainContent.addClass('l9');
            }
            fixPostCardWidth('artDetail', 'prenext-posts');
        });
        
    });
</script>

    

</main>




    <footer class="page-footer bg-color">
    
    <div class="container row center-align" style="margin-bottom: 15px !important;">
        <div class="col s12 m8 l8 copy-right">
            Copyright&nbsp;&copy;
            <span id="year">2019</span>
            <a href="/about" target="_blank">qinghuan</a>
            |&nbsp;Powered by&nbsp;<a href="https://hexo.io/" target="_blank">Hexo</a>
            |&nbsp;Theme&nbsp;<a href="https://github.com/blinkfox/hexo-theme-matery" target="_blank">Matery</a>
            <br>
            
            &nbsp;<i class="fas fa-chart-area"></i>&nbsp;站点总字数:&nbsp;<span
                class="white-color">58.9k</span>&nbsp;字
            
            
            
            
            
            
            <span id="busuanzi_container_site_pv">
                |&nbsp;<i class="far fa-eye"></i>&nbsp;总访问量:&nbsp;<span id="busuanzi_value_site_pv"
                    class="white-color"></span>&nbsp;次
            </span>
            
            
            <span id="busuanzi_container_site_uv">
                |&nbsp;<i class="fas fa-users"></i>&nbsp;总访问人数:&nbsp;<span id="busuanzi_value_site_uv"
                    class="white-color"></span>&nbsp;人
            </span>
            
            <br>
            
            <span id="sitetime">载入运行时间...</span>
            <script>
                function siteTime() {
                    var seconds = 1000;
                    var minutes = seconds * 60;
                    var hours = minutes * 60;
                    var days = hours * 24;
                    var years = days * 365;
                    var today = new Date();
                    var startYear = "2019";
                    var startMonth = "6";
                    var startDate = "28";
                    var startHour = "0";
                    var startMinute = "0";
                    var startSecond = "0";
                    var todayYear = today.getFullYear();
                    var todayMonth = today.getMonth() + 1;
                    var todayDate = today.getDate();
                    var todayHour = today.getHours();
                    var todayMinute = today.getMinutes();
                    var todaySecond = today.getSeconds();
                    var t1 = Date.UTC(startYear, startMonth, startDate, startHour, startMinute, startSecond);
                    var t2 = Date.UTC(todayYear, todayMonth, todayDate, todayHour, todayMinute, todaySecond);
                    var diff = t2 - t1;
                    var diffYears = Math.floor(diff / years);
                    var diffDays = Math.floor((diff / days) - diffYears * 365);
                    var diffHours = Math.floor((diff - (diffYears * 365 + diffDays) * days) / hours);
                    var diffMinutes = Math.floor((diff - (diffYears * 365 + diffDays) * days - diffHours * hours) /
                        minutes);
                    var diffSeconds = Math.floor((diff - (diffYears * 365 + diffDays) * days - diffHours * hours -
                        diffMinutes * minutes) / seconds);
                    if (startYear == todayYear) {
                        document.getElementById("year").innerHTML = todayYear;
                        document.getElementById("sitetime").innerHTML = "本站已安全运行 " + diffDays + " 天 " + diffHours +
                            " 小时 " + diffMinutes + " 分钟 " + diffSeconds + " 秒";
                    } else {
                        document.getElementById("year").innerHTML = startYear + " - " + todayYear;
                        document.getElementById("sitetime").innerHTML = "本站已安全运行 " + diffYears + " 年 " + diffDays +
                            " 天 " + diffHours + " 小时 " + diffMinutes + " 分钟 " + diffSeconds + " 秒";
                    }
                }
                setInterval(siteTime, 1000);
            </script>
            
            <br>
            
            <span id="icp"><img src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/medias/icp.png" style="vertical-align: text-bottom;" />
                <a href="http://beian.miit.gov.cn/" target="_blank">鲁ICP备19005295号-2</a>
            </span>
            
        </div>
        <div class="col s12 m4 l4 social-link social-statis">
    <a href="https://github.com/jinxiqinghuan" class="tooltipped" target="_blank" data-tooltip="访问我的GitHub" data-position="top" data-delay="50">
        <i class="fab fa-github"></i>
    </a>



    <a href="mailto:1196680037@qq.com" class="tooltipped" target="_blank" data-tooltip="邮件联系我" data-position="top" data-delay="50">
        <i class="fas fa-envelope-open"></i>
    </a>





    <a href="https://twitter.com/realljt" class="tooltipped" target="_blank" data-tooltip="关注我的Twitter: https://twitter.com/realljt" data-position="top" data-delay="50">
        <i class="fab fa-twitter"></i>
    </a>



    <a href="tencent://AddContact/?fromId=50&fromSubId=1&subcmd=all&uin=1196680037" class="tooltipped" target="_blank" data-tooltip="QQ联系我: 1196680037" data-position="top" data-delay="50">
        <i class="fab fa-qq"></i>
    </a>







    <a href="/atom.xml" class="tooltipped" target="_blank" data-tooltip="RSS 订阅" data-position="top" data-delay="50">
        <i class="fas fa-rss"></i>
    </a>

</div>
    </div>
</footer>

<div class="progress-bar"></div>


    <!-- 搜索遮罩框 -->
<div id="searchModal" class="modal">
    <div class="modal-content">
        <div class="search-header">
            <span class="title"><i class="fas fa-search"></i>&nbsp;&nbsp;搜索</span>
            <input type="search" id="searchInput" name="s" placeholder="请输入搜索的关键字"
                   class="search-input">
        </div>
        <div id="searchResult"></div>
    </div>
</div>

<script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/js/search.js"></script>
<script type="text/javascript">
$(function () {
    searchFunc('/search.xml', 'searchInput', 'searchResult');
});
</script>

    <!-- 回到顶部按钮 -->
<div id="backTop" class="top-scroll">
    <a class="btn-floating btn-large waves-effect waves-light" href="#!">
        <i class="fas fa-arrow-up"></i>
    </a>
</div>


    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/materialize/materialize.min.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/masonry/masonry.pkgd.min.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/aos/aos.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/scrollprogress/scrollProgress.min.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/lightGallery/js/lightgallery-all.min.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/js/matery.js"></script>

    <!-- Baidu Analytics -->

    <!-- Baidu Push -->

<script>
    (function () {
        var bp = document.createElement('script');
        var curProtocol = window.location.protocol.split(':')[0];
        if (curProtocol === 'https') {
            bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
        } else {
            bp.src = 'http://push.zhanzhang.baidu.com/push.js';
        }
        var s = document.getElementsByTagName("script")[0];
        s.parentNode.insertBefore(bp, s);
    })();
</script>

    
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/others/clicklove.js" async="async"></script>
    
    
    <script async src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/others/busuanzi.pure.mini.js"></script>
    

    

    

    
    <script type="text/javascript" color="0,0,255"
        pointColor="0,0,255" opacity='0.7'
        zIndex="-1" count="99"
        src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/background/canvas-nest.js"></script>
    

    
    
    <script type="text/javascript" size="150" alpha='0.6'
        zIndex="-1" src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/background/ribbon-refresh.min.js" async="async"></script>
    

    

    
    <script src="https://cdn.jsdelivr.net/gh/jinxiqinghuan/jinxiqinghuan.github.io/libs/instantpage/instantpage.js" type="module"></script>
    

</body>

</html>
